Vol 13, November 2001 NEWSLETTER FOR THE Canadian Antarctic Research Network Inside The Sirius Group and the East Antarctic Ice Sheet 1 The Sirius Group and the East Antarctic Ice Sheet The Remediation of Former Military Philip J. Holme and Stephen R. Hicock Stations in the Canadian Arctic – Its Relevance to Antarctica 4 The Antarctic Ice Sheet comprises two distinct ice sheets separated by the TransAntarctic Mountains, a massive range spanning the continent (Fig. 1). Some Recent Canadian Contributions to Antarctic and Large outlet glaciers from the East Antarctic Ice Sheet, the larger and higher of Bipolar Science 5 the two ice sheets, flow through mountain passes into the West Antarctic Ice Sheet. The last time the eastern sheet overtopped the mountains it deposited Aurora at the South Pole 6 the formation known as the Sirius Group – thin scattered patches of unsorted sediment at high elevations (mostly >1500 m). These deposits have been Twenty-fourth Antarctic Treaty the centre of intense debate since 1984 when researchers found they contained Consultative Meeting (XXIV ATCM), low concentrations of 3-million-year-old (Pliocene) marine diatoms (siliceous Saint Petersburg, Russia, microfossils). 8–20 July 2001 8 The discovery of diatoms in the Sirius Group led some to propose that the Eastern Antarctic Ice Sheet shrank by about one third during the Pliocene (the Report on the VIII SCAR “Webb-Harwood Hypothesis”) allowing a shallow seaway to form along the west- International Biology Symposium, ern (poleward) flank of the TransAntarctic mountains (Webb et al., 1984). When Vrije Universiteit, Amsterdam, the ice-sheet reformed it supposedly entrained marine sediments, depositing The Netherlands, them high in the mountains. Other studies have shown however that wind 27 August – 1 September 2001 10 transports diatoms – even into the interior of the continent. Marine and fresh- Council of Managers on National water diatoms have been found in snow at the South Pole (Kellogg and Kellogg, 18 Antarctic Programs (COMNAP), 1996). Furthermore, proxy records (δ O in deep-sea cores and drill-cores from Amsterdam, August 2001 11 the recently completed Cape Roberts Project) do not support a major Pliocene meltdown of the ice sheet (Barrett, 1999). In fact, cosmogenic dating shows that Polar Bears, Icebergs and the landscape in the Dry Valleys is older than 3 million years (e.g., Schafer et al., Saxifrage 12 1999). Most studies have therefore focused on the age of the Sirius and the tim- News in Brief 13 ing of the last expansion of the Eastern Antarctic Ice Sheet; and very little 2 The Allan Hills occupy a low point in the mountain range, making the site susceptible to overriding by the ice sheet during minor volume fluctuations. Field studies are also under way at Mt. Feather and Table Mountain, about 140 km south of Allan Hills. The Sirius Group records the most extensive glacial event at Allan Hills and comprises seven discrete patches of diamictite – pebbly to bouldery muddy sandstone – that rest on much older Permo-Triassic sedimentary rocks of the Beacon Supergroup (Fig. 2). Deposits cover about 4 km2, and reach a thickness of about 12 m. At Allan Hills the group consists of two distinct tillites, one resting on top of the other. Fieldwork in 1999 and 2000 focused on complet- ing the mapping of the deposits begun by a previous field party, and describing and sampling outcrops. This included measuring the orientation of stones and any abrasions on them as well as the nature and orientation of any deforma- tions within the Sirius Group to learn about the style of glaciation during deposition. Data gathered to date reveal that the Sirius Group was Figure 1 deposited by a wet-based glacier that completely overtopped Location of field sites. the nunatak and flowed from the south-southwest. The landscape on which the Sirius Group was deposited has research has been done on the geological nature of the Sir- largely been eroded away at Allan Hills and one goal of the ius Group. The objective of this project is to conduct a project is to reconstruct the pre-Sirius topography. This is detailed sedimentological study of the Sirius Group at three being done using GPS technology to map the sub- field sites around the Dry Valleys region of South Victoria Sirius surface as tie points and then extrapolating between Land (Fig. 1). From this we hope to learn whether the Sirius them. Group was deposited by valley glacier or continental ice In conjunction with this project, Hicock is studying sheet, whether by wet- or dry-based glacial ice, and whether the glacial character of drill cores taken from the Sirius by a single depositional event or by several overriding events. Group at Alan Hills and Table Mountain. After releasing We also hope to determine palæo-ice flow direction. stones from the sandy matrix of the tillite with an engraving The study has so far focused on deposits in the Allan tool (Hicock, 2000) the glacial features of the stones are Hills, a nunatak to the northwest of the Dry Valleys region. studied to interpret the conditions of tillite deposition and to reconstruct EAIS behaviour. At Mt. Feather in December 2000, we found a pair of boulder pavements in Sirius tillite; we are now preparing the first detailed report on Sirius tillite pavements and their relevance to the behaviour of the EAIS. CANADIAN ANTARCTIC RESEARCH NETWORK 3 Figure 2 Outcrop of Sirius Group showing subglacial shearing and attenuation of underly- Phil Holme of North Vancouver has a BSc in Geography from the ing coal (in Beacon Supergroup, black) into Sirius tillite. Ice-flow was from left to University of British Columbia and a MSc in Geology from the Uni- right. Hammer is 33 cm long. versity of Western Ontario. He is now working on his PhD in the School of Earth Sciences and Antarctic Research Centre, Victoria University of Wellington, New Zealand. Steve Hicock is professor References of Geology at the University of Western Ontario and an Honorary Barrett, P.J., 1999. Antarctic Climate History over the last 100 Million Years. Research Associate at Victoria University. He and Prof. Peter Terra Antarctica Reports, 3: 53–72. Barrett, Director of the Antarctic Research Centre, Victoria Hicock, S.R., 2000. Mesoscopic analysis of diamictite in semiconsolidated, non- oriented core. Journal of Sedimentary Research, 70: 967–969. University, co-supervise Phil Holme. Kellogg, D.E., and T.B. Kellogg, 1996. Diatoms in South Pole ice; implications for eolian contamination of Sirius Group deposits. Geology, 24: 115–118. Schafer, J.M., I. Leya, H. Baur, G.H. Denton, C. Schluchter, S. Ivy-Ochs and R. Wieler, 1999. Cosmogenic noble gas studies in the oldest landscape on Earth; surface exposure ages of the dry valleys, Antarctica. Earth and Plane- tary Science Letters, 167: 215–226. Webb, P.-N., D.M. Harwood, B.C. McKelvey, J.H. Mercer and L.D. Stott, 1984. Late Neogene and older Cenozoic microfossils in high elevation deposits of the Transantarctic Mountains: Evidence for marine sedimentation and ice- volume variation on the east Antarctic craton. Antarctic Journal of the United States, 18: 96–97. 4 The Remediation of Former Military Stations in the Canadian Arctic – Its Relevance to Antarctica John S. Poland In the 1950s, the US government constructed the Distant 2. Landfills and dumps Early Warning (DEW) Line to detect Soviet aircraft or mis- Historic waste disposal generally consisted of dumps siles approaching from over the pole. Its 42 radar stations (debris areas with varying amounts of granular cover). stretched from Komakuk Beach, near the Alaska border to Currently each of these is evaluated according to long- Cape Dyer on the east coast of Baffin Island. In the 1960s term environmental risk potential, and remediation may 21 DEW Line stations were abandoned. The advent of satel- entail the placement of additional cover, the incorpora- lite communications and new technology rendered the tion of a leachate control system, or complete excavation. remaining DEW Line stations obsolete and in 1985, Canada 3. Physical debris and building demolition and the United States signed an agreement to replace the Generally the protocol distinguishes hazardous from non- remaining 21 facilities with a modernized radar surveillance hazardous materials and also deals with the disposal of system called the North Warning System. Plans to remediate barrels and their contents. the abandoned sites began on completion of this process, in Indian and Northern Affairs Canada (INAC) and the 1993. Department of National Defence (DND) are each responsi- The Environmental Sciences Group (ESG), led by Dr. ble for remediating 21 DEW Line sites. The first major Ken Reimer of the Royal Military College and the Analytical cleanup took place in 1995–96 at the former military site Services Unit (ASU), led by Dr. John Poland of Queen’s Uni- adjacent to Iqaluit, Nunavut. The Town (now City) of Iqa- versity (both at Kingston, Ontario) conducted environmental luit provided equipment and workers while the ASU provid- assessments of all the DEW Line and associated sites. In ed management, solved problems as they arose, conducted 1991, relevant Canadian government departments agreed to all engineering work (in conjunction with UMA Engineer- the DEW Line Clean Up Protocol. It has since undergone ing) and arranged the disposal of contaminated materials. minor modifications and additions to accommodate the con- I serve as INAC’s scientific adviser for Arctic contami- cerns of local residents and to incorporate lessons learned nated site cleanup. INAC has identified over 1,100 other during the cleanup work. contaminated sites in the Canadian north, including the Res- The DEW Line Clean Up Protocol divides the remedi- olution Island site, one of Canada’s largest remediation pro- ation tasks into three categories: jects.